The Duct Encapsulation is done by spray 1" of closed cell spray foam insulation over existing ducts. Tite 'n' True Foam Duct Encapsulation has a superior R-value by making it air tight. After blown in cellulose is added to the space around the ducts. Now, when your furnace or air conditioning heats or cools the air, that heating/cooling is delivered to your rooms without loss along the way.